SeaWorld will stop breeding orca whales in captivity, the company announced on Thursday, a move applauded by animal rights activists who havebeen calling for an end to the public exhibition of the animals altogether for years.

“By making this the last generation of orcas in our care and reimagining how guests will experience these beautiful animals, we are fulfilling our mission of providing visitors to our parks with experiences that matter,” said Joel Manby, president and CEO of SeaWorld Entertainment Inc.

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The breeding program will end immediately, and the killer whales currently at its parks will be the last, Manby said.

The Orlando-based theme park operator has faced falling visitor numbers and years of criticism over its treatment of the captive marine mammals as well as pressure from animal rights activists.

The director of Peta, Mimi Bekhechi, welcomed the news, but called for those still in captivity to be allowed ocean access.

“SeaWorld must open its tanks to the oceans to allow the orcas it now holds captive to have some semblance of a life outside these prison tanks,” said Bekhechi in a statement.

But SeaWorld said the remaining whales – including a pregnant whale, Takara – will live out the rest of their lives under the care of their veterinary staff, as releasing them into the wild will likely kill them.

“These orcas have never lived in the wild and could not survive in oceans that include environmental concerns such as pollution and other manmade threats,” said the company on its site. Although a few of SeaWorld’s orcas were born in the wild, the majority were bred in captivity by the company.

“The decision to end its orca breeding program globally and to commit to ending the collection of exhibit animals from the wild, as well as to a ‘no orca’ policy should SeaWorld expand its brand into new international markets, is a monumental and important first step forward in achieving a more humane business model for the company,” said the Animal Welfare Institute.

Data from the Whale and Dolphin Conservation says SeaWorld has 23 orcas in its US parks. Eleven of those live in its San Diego park.

Jon Reilly, then president of SeaWorld San Diego, opposed the decision, declaring “a ban on breeding would sentence these animals to a slow extinction in our care”.

The 2013 documentary Blackfish, which told the story of Tilikum, a SeaWorld whale kept in captivity and involved in the deaths of several people, propelled the theme park’s treatment of orcas into the public eye.

Democratic congressman Adam Schiff, who introduced the Orca Act, a law which would phase out breeding of orcas in captivity, supported the news.

“These changes are something that advocates have been urging for years, and I think SeaWorld will find that visitors will reward their actions with a renewed interest in the parks,” he said.

Rather than training whales to perform tricks on demand for treats, the theme park will introduce “new, inspiring natural orca encounters”. The end to circus-like shows was first announced last November as part of the company’s overhaul aimed at stemming financial losses.

Existing pools will be renovated to more closely depict a natural setting. Whales will appear to the public in regular shows, but “these programs will focus on orca enrichment, exercise and overall health”, read the announcement on SeaWorld’s site.

The new shows will start in the San Diego park next year, before being rolled out to San Antonio and Orlando in 2019.

The company also announced a new partnership with the Humane Society. SeaWorld has committed to donate $50m over the next five years to fight illegal fishing of whales and seals and end shark finning.

Timeline to the ban

24 February 2010: SeaWorld trainer Dawn Brancheau killed by Tilikum.

January 2013: Blackfish premieres at Sundance.

July 2013: Blackfish released nationally.

December 2013: SeaWorld attendances drops 5% by the end of the year.

2 December 2014: Orca Amaya is born at SeaWorld San Diego, currently the youngest whale at SeaWorld.